1. Field of the Invention
The present invention relates to an optical axis adjustment in a surveying machine.
2. Description of the Related Art
In a surveying machine, such as a total-station (an electronic tacheometer), an electronic/optical theodolite, a leveling machine, and so on, a sighting optical system for sighting an object, and a light-transmitting optical system for transmitting light radiated from a light source to the object, are provided. Generally, a signal target or pole is located at a surveying-position (a station), and the signal target or pole is sighted using the sighting optical system. The light radiated from the light source passes the light-transmitting optical system and is emitted from the surveying machine toward a sighted point on the signal target or pole.
An optical axis of the light-transmitting optical system is adjusted in advance such that the optical axis coincides with an optical axis of the sighting optical system. Consequently, the light, radiated from the surveying machine via the light-transmitting optical system, reaches the sighted point on the signal target. Thus, a precise survey can be performed. Namely, a distance, an angle, and a horizontal level can be precisely measured.
However, the optical axis of the light-transmitting optical system occasionally displaces relative to the optical axis of the sighting optical system because of a change of temperature, or humidity. In this case, the point where the light reaches does not coincide with the sighted point so that a precise measurement cannot be performed. To match the two optical axes, it is necessary to manually adjust the position of a reflecting mirror, provided as part of the light-transmitting optical system. However, this adjustment is very troublesome and very difficult for the user.
Therefore, an object of the present invention is to provide a surveying machine that can provide precisely measurements at any time without requiring manual adjustments of the optical axis.
A surveying machine according to the present invention includes a sighting optical system for sighting an object, and a light-transmitting optical system. For example, a signal target such as a reflecting sheet, or a reflecting prism, or similar, is used as an object to be sighted, and is arranged at a station. The sighting optical system has, for example, an objective lens, a focusing glass and an erecting optical ember, such as an erecting prism, and an eyepiece. The light-transmitting optical system transmits a beam for surveying, radiated from a light source, to the object. When the surveying machine is a leveling machine or an electronic/optical theodolite, the beam for sighting, such as a Laser, is emitted and transmitted, on the other hand, when the surveying machine is a total-station or an electronic distance-meter, the beam for measuring a distance between the surveying machine and the object is emitted and transmitted.
The surveying machine of the present invention includes a deviation detector and an optical axis adjuster. The deviation detector detects a gap, namely, a deviation between an optical axis of the sighting optical system and an optical axis of the light-transmitting optical system. When the beam, passing through the light-transmitting optical system, does not progress along the optical axis of the sighting optical system toward the sighted point, a deviation occurs. The deviation detector detects the deviation by detecting the situation where the beam does not reach the pointed sighted by the sighting optical system. Hereinafter, the optical axis of the sighting optical system is designated as the xe2x80x9cfirst optical axisxe2x80x9d and the optical axis of the light-transmitting optical system is designated as the xe2x80x9csecond optical axisxe2x80x9d.
The optical axis adjuster automatically adjusts at least one of the first optical axis and the second optical axis so as to correct the deviation. For example, the optical axis adjuster adjusts the second optical axis such that the beam progress along the first optical axis toward the sighted point, or the optical axis adjuster adjusts the first optical axis such that the first optical axis is along the progressing direction of the beam, which corresponds to the second optical axis.
As the deviation is automatically detected and is automatically corrected, a precise distance, precise level, or precise angle, etc., is obtained using the surveying machine.
To maintain the stability of the sighting optical system, namely, not to change the first optical axis, preferably, the optical axis adjuster adjusts the second optical axis without adjusting the first optical axis. Generally, the light-transmitting optical system includes al least one of a reflecting optical member and a refracting optical member. In this case, the optical axis adjuster includes a positioning changer that changes a position of the reflecting optical member, or the refracting optical member. To compensate for the deviation, the optical axis adjuster adjusts the second optical axis by changing the position of the reflecting or refracting optical member in accordance with the deviation.
When the surveying machine is a total-station or a digital distance-meter, a distance detector is provided in the surveying machine. The distance detector measures the distance between the surveying machine and the object by receiving a beam of reflected light from the object.
To detect the deviation by utilizing the construction of prior surveying machines as much as possible, preferably, the deviation detector detects the deviation on the basis of the reflected light, from the object, which passes through the sighting optical system. Namely, the deviation detector detects the deviation from the difference between the first optical axis and the progressing-direction of the beam, which is included in reflected light from the object. To detect the deviation as two-dimensional information, preferably, the deviation detector includes a two-dimension deviation detector that receives the beam and detects the deviation represented by two-dimensional coordinates defined on a focal plane. The two-dimension deviation detector detects the deviation on the basis of an incidence position of the beam and a preset base-position corresponding to the first optical axis.
In the case of the total-station or the digital distance-meter, a specific area reflecting optical member is arranged in the sighting optical system. The specific area reflecting optical member has a reflecting area and a penetrating area. The reflecting area selectively reflects the beam from among the reflected light, to the distance detector. The penetrating area, namely, transmitting area enables all of the reflected light to penetrate. Consequently, both the distance and the deviation are detected on the basis of the beam passing through the sighting optical system.
For example, the specific area reflecting optical member is constructed of a single member, in which the reflecting area and the penetrating area are formed in a body, or the specific area reflecting optical member is constructed of a plurality of members, in which the reflecting area and penetrating area are formed separately.
To detect the deviation by utilizing the beams passing through the sighting optical system, preferably, a selective reflecting optical member or a selective penetrating optical member is arranged in the sighting optical system. The selective reflecting optical member divides the beam from the reflected light by reflecting the beam, whereas the selective penetrating optical member divides the beam from the reflected light by allowing only the beam to penetrate. For example, the selective reflecting optical member has a first dichroic surface that reflects only light having a wavelength area corresponding to the beam. On the other hand, the selective penetrating optical member has a second dichroic surface that enables only light having a wavelength area corresponding to the beam to penetrate.
To detect the deviation by utilizing an optical member prepared as one of the elements of the sighting optical system, a selective penetrating optical member is used, that is an erecting prism having a second dichroic surface. The erecting prism is provided as one of the sighting optical system to erect an object image. Accordingly, the deviation is detected without including a new optical member for detecting the deviation in the sighting optical system.
An automatic optical axis adjusting apparatus of a surveying machine according to another aspect of the present invention has a deviation detector and an optical axis adjuster. The surveying machine has a sighting optical system for sighting an object, and a light-transmitting optical system for transmitting a beam for surveying. The beam is radiated from a light source, to the object. The deviation detector detects a deviation between a first optical axis corresponding to the sighting optical system and a second optical axis corresponding to the light-transmitting optical system. The optical axis adjuster automatically adjusts at least one of the first optical axis and the second optical axis so as to correct the deviation.